Glazing unit having three or more glass sheets and having a low thermal edge, and method of making same

ABSTRACT

A glazed unit having three sheets includes a pair of outer glass sheets secured to outer legs of a spacer having a generally U-shaped cross section. On the base of the spacer between the outer legs is provided a layer of pliable material having a generally U-shaped cross section and having a desiccant therein. A third or intermediate glass sheet has its edge portion in the groove formed by the layer of pliable material. Movement of the third sheet toward an outer glass sheet is limited by the cooperation of the layer of the pliable material and portion of the outer legs of the spacer at the corners of the unit bent inwardly to move the layer of pliable material at the corner toward the unit during fabrication of the unit. A method is also disclosed for making the triple glazed unit and for filling the compartments between the sheets with an insulating gas e.g. Argon.

FIELD OF THE INVENTION

This invention relates to a glazing unit having three or more glasssheets, and, in particular to a triple glazed trait having a pair ofouter glass sheets separated by an edge assembly having low thermalconductivity, the edge assembly including a spacer arrangement forsupporting a glass sheet between the outer glass sheets, and method ofmaking, and nozzle for use in the fabrication of the triple glazed unit.

BACKGROUND OF THE INVENTION

European Patent Application Publication Number 0 475 213 A1 published18.03.92 Bulletin 92/12 (hereinafter "The EP Application") based on U.S.Patent Applications Ser. Nos. 578,697 filed Sep. 4, 1990; 578,696 filedSep. 4, 1990, and 686,956 filed Apr. 18, 1991, teaches a glazing unithaving an edge assembly having low thermal conductivity and a method ofmaking same. In general, The EP Application teaches an insulating unithaving a pair of glass sheets about an edge assembly to provide acompartment between the sheets. The edge assembly has a U-shaped spacerthat is moisture and/or gas impervious, and has materials selected andsized to provide the edge assembly with a predetermined RES-value (asdefined and determined in the disclosure of The EF Application). The EPApplication further discloses a triple glazed unit having a low thermalconducting edge.

U. S. Pat. No. 4,149,348 teaches a technique for making a triple glazedunit. In general, the triple glazed unit includes a pair of outer glasssheets separated by a spacer-dehydrator element, or metal spacer, havinga groove to maintain a third glass sheet between the outer two glasssheets.

Although the triple glazed unit taught in U.S. Pat. No. 4,149,348 isacceptable, there are limitations. More particularly, thespacer-dehydrator element is structurally stable and is formed with agroove prior to its use. The spacer has desiccant therein; therefore, itis stored in a dry environment to prevent adsorption of moisture by thedesiccant. The metal spacer has to be formed to have a groove; theadditional forming increases the fabrication cost of the spacer.Further, the groove formed in the spacer disclosed is U.S. Pat. No.4,149,348 maintains the third glass sheet spaced from the outer sheets;therefore, the groove has to be properly sized to prevent movement ofthe inner sheet relative to the outer sheets.

As can be appreciated, it would be advantageous to provide an insulatingunit having three or more sheets that does not require storage ofprefabricated materials e.g. a spacer-dehydrator element having agroove, does not require shaping the spacer to have a groove, and doesnot depend solely on the groove formed in the spacer to secure theintermediate sheet in position.

SUMMARY OF THE INVENTION

This invention relates to a glazing unit having at least three glasssheets. The unit includes a spacer having a receiving surface tomaintain the glass sheets in spaced relationship to one another. In oneembodiment of the invention, the spacer has a base, a first wall and asecond wall each extending upward from the base to provide the spacerwith a generally U-shaped cross section with the receiving surfacebetween the walls. The glass sheets are secured to the spacer, e.g. by amoisture and/or gas impervious adhesive on outer surfaces of the wallsof the spacer to provide sealed compartments between the outer glasssheets e.g. a sealed compartment between one of the outer sheets and theintermediate sheet and a sealed compartment between the other outersheet and the intermediate sheet. A layer of a flowable, pliablematerial has a generally U-shape cross section to provide a groove toreceive marginal edge portions of the third or intermediate glass sheet.Facilities are provided to maintain the intermediate sheet in asubstantially fixed relationship to the outer glass sheets. In oneembodiment of the invention, the wall portions of the spacer at selectedcorners of the finished unit are bent toward one another and spaced asufficient distance to receive the intermediate glass sheettherebetween. The wall portions of the spacer bent toward one anotherbiases the pliable material on the receiving surface of the spacertoward the intermediate sheet to maintain the intermediate sheet inposition.

In a further embodiment of the invention a desiccant is provided in thepliable material, an insulating gas e.g. argon gas is provided in thecompartments formed by adjacent sheets and the spacer, and/or the edgeassembly including the spacer, the adhesive and the pliable materialhave a RES-value equal to or greater than 10 as measured using ANSYS.

The invention further relates to a method of making an insulatingglazing unit having at least three sheets including the steps ofproviding two glass sheets having substantially the same peripheralconfiguration and dimensions and a spacer of a predetermined lengthhaving a receiving surface. In one embodiment of the invention, thespacer is formed by providing notches at selected positions on a flatbendable substrate to provide opposed pair of notches defining bendareas of the spacer. The flat substrate is shaped to provide a spacerhaving a generally U-shaped cross section defined by a first outer leg,a base and a second outer leg. A shaped layer of a flowable materiale.g. a pliable material or a material that hardens after flowing and isdimensionally stable, having a groove is provided on the receivingsurface of the spacer. The glass sheet or sheets to be positionedbetween the outer sheets has peripheral configurations similar to theouter glass sheets and peripheral dimensions less than the outer sheets.The spacer is positioned around the edge of the intermediate sheet withthe edges of the intermediate sheet in the groove. The intermediatesheet is maintained in a generally fixed position relative to the outerglass sheets by the pliable material and/or the spacer. In oneembodiment of the invention, as the spacer having the U-shaped crosssection is positioned around the periphery of the third sheet, the wallportions of the spacer at the bend areas are bent inward toward oneanother urging the pliable material toward the corner areas of theintermediate sheet. The layer of the pliable material may have adesiccant mixed therein. The outer glass sheets are secured to the outersurfaces of the legs of the spacer by an adhesive, e.g. by a moistureand/or gas impervious adhesive.

The invention still further relates to a nozzle to deposit the shapedlayer of the flowable material on the spacer. The nozzle includes aplatform having a shaping tip or member mounted therein. The shaping tipat a first end has converging sides and at the opposite end has sidesthat are generally parallel to one another. The elevation of the shapingtip at the first end is different e.g. lower, than the elevation of theshaping tip at the second end. Holes for moving material therethroughare in the nozzle, e.g. one hole on each side of the tip and one in thetip. The converging end of the tip and the different elevations of thetip minimize, if not eliminate, tailing when moving e.g. pumping of thematerial has been discontinued.

The invention still further relates to an injector arrangement forfilling the compartments between the sheets with an insulating gas,

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a frontal view of a triple glazed unit incorporating featuresof the invention.

FIG. 2 is the view taken along lines 2--2 of FIG. 1.

FIG. 3 is a view similar to the view of FIG. 2 illustrating anotherembodiment of an edge assembly incorporating features of the invention.

FIG. 4 is a fragmented elevated view of a substrate having portionsremoved prior to forming a spacer used in the practice of the invention.

FIG. 5 is an elevated side view of a nozzle incorporating features ofthe invention for extruding a shaped layer of adhesive on the base of aspacer in accordance to the teachings of the invention.

FIG. 6 is a plane view of the tip of the nozzle illustrating features ofthe invention.

FIG. 7 is a side view of the tip of the invention.

FIG. 8 is a view similar to the view of FIG. 6 illustrating anotherembodiment of a tip incorporating features of the invention.

FIG. 9 is a view similar to the view of Fig, 7 illustrating furtherdetails of the tip of FIG. 8.

FIG. 10 is a side elevated view of an injector arrangement of theinvention for filling the compartments of a glazing unit with aninsulating gas.

FIG. 11 is an end view of the injector arrangement of FIG. 10.

FIG. 12 is a view illustrating the use of the injector arrangement ofthe invention to fill a unit having a single compartment with aninsulating gas.

FIG. 13 is a view similar to the view of FIG. 12 illustrating the use ofthe injector arrangement of the instant invention to fill a unit havingtwo sealed compartments.

FIG. 14 is a view similar to the view of FIG. 2 showing an insulatingunit having three compartments incorporating features of the invention.

FIG. 15 is a view similar to the view of FIG. 1 illustrating anotherembodiment of the invention.

FIG. 16 is a view taken along lines 16--16 of FIG. 15.

BRIEF DESCRIPTION OF THE INVENTION

The glazing unit of the instant invention will be discussed having theedge assembly disclosed in The EP Application which teachings are herebyincorporated by reference. As will be appreciated the instant inventionis not limited to the configuration of the spacer disclosed therein, andother spacer configurations may be used in the practice of the inventionto maintain the at least three spaced sheets in spaced relationship toone another; i.e. prevent or minimize movement of the intermediate sheettoward an outer sheet.

With reference to FIGS. 1 and 2 there is shown a glazing unit 20incorporating features of the invention. With specific reference to FIG.2 the unit 20 includes a pair of outer sheets 22 and 24 and anintermediate sheet 26. The outer sheets 22 and 24 and the intermediatesheet 26 are maintained in spaced relationship by an edge assembly orspacer arrangement 28.

In the following discussion the sheets 22, 24 and 26 are referred to asglass sheets; however, as will become apparent, the materials of thesheets are not limited to glass and any one or all of the sheets may bemade of any similar or dissimilar material e.g. plastic, metal or wood.Further, one or more of the sheets may be coated e.g. glass or plastictransparent sheets may have an opaque coating of the type used in makingspandrels. Still further, one or more of the glass or plastictransparent sheets may have an environmental coating on one or more ofthe sheet surfaces to selectively pass predetermined wavelength rangesof light. More particularly, glass sheets may have coatings to filterportions of the infrared range e.g. low emissivity coatings and/orcoatings to reflect light e.g. reflective coatings. Although notlimiting to the invention, coatings disclosed in U.S. Pat. Nos.4,610,711; 4,806,220 and 4,853,257 which teachings are herebyincorporated by reference may be used in the practice of the invention.Still further, one or more of the glass sheets may be coated and oruncoated colored sheets. Although not limiting to the invention, coloredsheets of the type disclosed in U.S. Pat. Nos. 4,873,206; 5,030,593 and4,792,536 which teachings are hereby incorporated by reference may beused in the practice of the invention.

The outer glass sheets 22 and 24 may have the same peripheralconfiguration and dimensions; however, as can be appreciated, one outerglass sheet may be larger than the other outer glass sheet and may havea different peripheral configuration.

The edge assembly 28 includes a spacer 30 having a generally U-shapedcross section as shown in FIG. 2, an adhesive layer 32 on outer surfacesof outer legs 34 and 36 of the spacer 30 and a shaped layer 38 ofmaterial (to be discussed below) on inner surface 40 of base 42 of thespacer 30. A layer 44 of a material similar to or dissimilar to thematerial of the layers 32 may be provided over outer surface 46 of thebase 42 of the spacer 30 as shown in FIG. 2.

As can be appreciated, the configuration of the spacer is not limitingto the invention and may have any cross section provided it has asurface to receive the shaped layer 38 and the intermediate glass sheet26. For example and with reference to FIG. 3, there is shown a unit 50having the glass sheets 22 and 24 separated by an edge assembly 52having the adhesive layers 32 to secure the glass sheets 22 and 24 tospacer 54. The spacer 54 may be made of wood, metal or plastic havingany cross sectional configuration and a receiving surface 56 to receivethe shaped layer 38 in a similar fashion as the surface 40 of the spacer30 of the edge assembly 28 shown in FIG. 2.

As discussed, the spacers 30 and 54 may be made of any material andconfiguration that preferably provides structural stability to maintainthe outer glass sheets 22 and 24 in spaced relationship to one anotherwhen biasing forces are applied to secure the glazing unit in a sash ora curtainwall system. Further the spacers 30 and 54 should have asubstantially flat surface to receive the shaped layer 38. Although thespacers 42 and 54 may be made of any material and have any configurationprovided it has a receiving surface, it is preferred that the spacerhave low thermal conductivity so that the edge assembly 28 shown in FIG.2, and the edge assembly 52 shown in FIG. 3, have a low thermalconductivity or high RES-value and are made of moisture and/or gasimpervious materials.

In regards to the edge assembly having a low thermal conductivity,spacers made of aluminum conduct heat better than spacers made of metalcoated steels e.g. galvanized or tin plated steel, spacers made of metalcoated steels conduct heat better than spacers made of stainless steels,and spacers made of stainless steels conduct heat better than spacersmade of plastics. Plastic provides a better spacer from the standpointof low thermal conductivity; however, metal is preferred for spacersbecause it is easier to shape and lends itself more easily to automationthan plastic.

The EP Application discusses in detail how the value of resistance toheat flow of the edge assembly per unit length of perimeter, defined asRES-value is determined and how the contributions of the components ofthe edge assembly to the RES-value are determined. The following is aless detailed discussion.

The heat loss through an edge of a unit is a function of the thermalconductivity of the materials used, their physical arrangement, thethermal conductivity of the frame and surface film coefficient. Surfacefilm coefficient is transfer of heat from air to glass at the warm sideof the unit and heat transfer from glass to air on the cold side of theunit. The surface film coefficient depends on the weather and theenvironment. Since the weather and environment are controlled by natureand not by unit design, no further discussion is deemed necessary. Theframe or sash effect is not relevant in the present discussion becausethe discussion is directed to the thermal conductivity of the materialsat the unit edge and their physical arrangement.

The resistance of the edge of a unit to heat loss for an insulating unithaving sheet material separated by an edge assembly is given by equation(1).

    RHL=G.sub.1 +G.sub.2 +...+G.sub.n +S.sub.1 +S.sub.2 +...+S.sub.n(1)

where

RHL is the resistance to edge heat loss at the edge of the unit inhour - °F./BTU/inch of unit perimeter (Hr-°F./BTU-in.)

G is the resistance to heat loss of a sheet in Hr-°F./BTU-in.

S is the resistance to heat loss of the edge assembly in Hr-°F./BTU-in.

For an insulating unit having two sheets separated by a single edgeassembly equation (1) may be rewritten as equation (2).

    RHL=G.sub.1 +G.sub.2 +S.sub.1                              (2)

The thermal resistance of a material is given by equation (3).

    R=L/kA                                                     (3)

where

R is the thermal resistance in Hr-°F./BTU-in.

k is thermal conductivity of the material in BTU/hour-inch-°F. 1 is thethickness of the material as measured in inches along an axis parallelto the heat flow.

A is the area of the material as measured in square inches along an axistransverse to the heat flow.

The thermal resistance for components of an edge assembly that lie in aline substantially perpendicular or normal to the major surface of theunit is determined by equation (4).

    S=R.sub.1 +R.sub.2 +...+R.sub.n                            (4)

where S and R are as previously defined.

In those instances where the components of an edge assembly lie along anaxis parallel to the major surface of the unit, the thermal resistance(S) is defined by the following equation (5). ##EQU1## where R is aspreviously defined.

Combining equations (2), (4) and (5), the resistance of the edge of theunit 20 shown in FIG. 2 to heat flow may be determined by followingequation (6). ##EQU2## where RHL is as previously defined, R₂₂ and R₂₄are the thermal resistance of the glass sheets,

R₃₂ is the thermal resistance of the adhesive layer 32,

R₄₄ is the thermal resistance of the adhesive layer 44,

R₃₄ is the thermal resistance of the outer legs 34 of the spacer 30,

R₄₂ is the thermal resistance of the base 42 of the spacer 30,

R₃₈ is the thermal resistance of the adhesive layer 38, and

R₂₆ is the thermal resistance of the middle sheet 26.

For ease of discussion, equation (6) does not consider the thermalconducting contribution of the intermediate sheet 26. If the thermalconductivity contribution of the intermediate sheet 26 were considered,it is expected that the value of RHL in equation (6) would be about 10%higher than the value calculated without considering the contribution ofthe thermal conductivity of the intermediate sheet 26. In the RES-valuegiven in the specification and claims the RES-value does not include thecontribution of the intermediate sheet 26.

Although equation (6) shows the relation of the components to determineedge resistance to heat loss, Equation 6 is an approximate method usedin standard engineering calculations. Computer programs are availablewhich solve the exact relations governing heat flow or resistance toheat flow through the edge of the unit.

One computer program that is available is the thermal analysis packageof the ANSYS program available from Swanson Analysis Systems Inc. ofHouston, Pa. The discussion of the edge resistance of the edge assembly(excluding the outer glass sheets) will now be considered. The edgeresistance of the edge assembly is defined by the inverse of the flow ofheat that occurs from the interface of the glass sheet 22 and adjacentsealant layer 32 at the inside side of the unit to the interface ofglass sheet 24 and adjacent sealant layer 32 at the outside side of theunit per unit increment of temperature, per unit length of edge assemblyperimeter (including the intermediate sheet). The outer glass sealantinterfaces are assumed to be isothermal to simplify the discussion.Support for the above position may be found, among other places, in thepaper entitled Thermal Resistance Measurements of Glazing SystemEdge-Seals and Seal Materials Using a Guarded Heater Plate Apparatuswritten by J. L. Wright and H. F. Sullivan ASHRAE TRANSACTIONS 1989, V.95, Pt.2.

In the discussion of the instant invention and in the claims, RES-valueis defined as the resistance to heat flow of the edge assembly e.g. theedge assembly 28 in FIG. 2 and the edge assembly 52 in FIG. 3, per unitlength of perimeter.

With continued discussion of the instant invention, the materials of theadhesive layers 32 and the layer 44 are not limiting to the inventionand are preferably a material that is moisture and/or gas impervious toprevent the ingress of moisture into the compartment between the sheets.Although not limiting to the invention, butyl hot melts of the type soldby H. B. Fuller e.g. H. B. Fuller 1191 may be made in the practice ofthe invention. Units filled with an insulating gas e.g. Argon preferablyhave the adhesive layer 32 and the layer 44 of a moisture and/or gasimpervious material to maintain the insulating gas in the compartmentbetween the sheets 24, 26 and 26, 22. It is recommended that theadhesive layer 32 or sealant layer 32 be thin and long to reduce thediffusion of the insulating gas out of the compartments of the unit oratmosphere's gas into the compartments of the unit. More particularly,increasing the thickness of the layer 32 i.e. the distance between theglass sheet and the adjacent leg of the spacer while keeping all otherconditions constant increases the diffusion rate, and increasing thelength of the layer 32 i.e. the distance between the top of the outerleg of the spacer and the peripheral edge of the sheets or the outersurface 46 of the spacer 30 as viewed in FIG. 2 while keeping all otherconditions constant decreases the diffusion rate of gas through theadhesive layer 32. The invention may be practiced with the adhesivelayer 32 having a thickness less than about 0.125 inch (0.32 cm) andmore particularly, of about 0.005 inch (0.013 cm) to about 0.125 inch(0.32 cm), preferably about 0.010 inch (0.025 cm) to about 0.020 inch(0.050 cm) and most preferably about 0.015 inch (0.38 cm), and a heightof greater than about 0.010 inch (0.025 cm), and more particularly, ofabout 0.010 inch (0.025 cm) to about 0.50 inch (1.27 cm), preferablyabout 0.125 inch (0.32 cm) to about 0.50 inch (1.27 cm) and mostpreferably about 0.200 inch (0.50 cm).

As can be appreciated the thickness and length of the layer 32 maychange as the moisture and/or gas resistance value of the moistureand/or gas impervious material changes. For example as the resistancevalue of the material increases, the thickness of the layer 32 may beincreased and the length of the layer 32 decreased and as the resistancevalue of the material decreases, the thickness of the layer 32 should bedecreased and the length of the layer 32 should be increased. Adhesivesthat may be used in the practice of the invention include but are notlimited to butyls, silicons, polyurethane adhesives and are preferablybutyls and polyurethanes such as H. B. Fuller 1191, H. B. Fuller 1081Aand PPG Industries, Inc. 4442 butyl sealant.

With respect to the loss of the fill gas e.g. an insulating gas such asArgon from the unit, in practice the length and thickness of the layer32 are chosen in combination with the gas permeability of the materialso that the rate of loss of the fill gas matches the desired unitperformance lifetime. The ability of the unit to contain the fill gas ismeasured using a European procedure identified as DIN 52293. Preferably,the rate of loss of the fill gas should be less than 5% per year and,more preferably, it should be less than 1% per year.

The preferred material for the layer 32 should have a moisturepermeability of less than 20 gm mm/M² day using ASTM F 372-73 and morepreferably less than 5 gm mm/M² day.

As can be appreciated, the spacer 30 should also be made of a materialthat is moisture and/or gas impervious e.g. metal or plastic of the typedisclosed in The EP Application such as but not limited to metal coatedsteels, stainless steel, gas pervious spacers covered with a metal orpolyvinylidene chloride film and/or a halogenated polymeric material.

In FIG. 2 there is shown the layer 44 provided on the outer surface 46of the spacer 30. The layer 44 may be a material similar to the materialof the layers 32 and is preferably non-tacky so that the units whenstored or shipped do not stick to the supporting surface. Further whenthe units have the layer 44, the spacer 30 is preferably below theperipheral edges of the sheets 22 and 24 to provide a channel to receivethe layer 44. The thickness of the layer 44 is not limiting to theinvention and where used increases the RES-value because of the thermalinsulating properties of the sealant. The invention may be practicedwith no layer 44 to a layer 44 having a thickness of about 0.50 inch(1.27 cm), preferably about 0.062 inch (0.16 cm) to about 0.250 inch(0.64 cm) and most preferably about 0.150 inch (0.38 cm). Preferably thelayer 44 has similar moisture and gas resistance values on the layers32.

With specific reference to FIG. 2, the layer 38 is shaped to provide agroove 48 to receive the peripheral edge of the intermediate sheet 26.The material selected for the layer 38 is a material that is flowableonto the receiving surface 40 of the base 42 of the spacer 30 andadheres thereto as contrasted to a preformed material of the type taughtin U.S. Pat. No. 4,149,348. Using a flowable material in accordance tothe disclosure of the instant invention provides for ease of automatingthe fabrication of the spacer, edge assembly and/or units, as will beappreciated in the following discussion. The term "flowable material"means a material that may be flowed onto a surface, for example but notlimited to the invention by extrusion or pumping. In the selection ofthe materials for the layer 38, consideration has to be given tomaintaining the intermediate sheet 26 in position, e.g. prevent or limitits movement toward one of the outer sheets. Materials that are mostpreferably used in the practice of the invention are those materialsthat are flowable and remain pliable after flowing and materials thatare flowable and harden e.g. are dimensionally stable after flowing. Theterm "pliable materials" means materials that have a Shore A Hardness ofless than 45 after 10 seconds under load. Pliable materials that may beused in the practice of the invention have a Shore A Hardness of lessthan 40 after 10 seconds. Pliable materials used in the practice of theinvention had a Shore A Hardness of 25 with a range of 20-30 after 10seconds. The term "hardened material" is a material other than a pliablematerial.

In the instance where the intermediate sheet 26 is to be held inposition only by the shaped layer 38, the layer 38 should be a materialthat is flowed onto the surface 40 of the spacer to provide the groovelayer 38, and, thereafter, the material is sufficiently rigid tomaintain the intermediate glass sheet in position. In the instance wherethe material is flowed onto the base and is not sufficiently rigid, itis recommended that facilities be provided to secure the intermediateglass in position. Also if the material of the layer 38 requires time tobecome sufficiently rigid and the unit is to be moved prior to settingof the layer 38, it is recommended that facilities be provided to securethe intermediate glass in position. The preferred manner in eitherinstance is to use the spacer 30 alone or in combination with the layer38 in a manner to be discussed below. Other external facilities such asspacer blocks may be used in the practice of the invention.

The EP Application teaches a spacer frame having a continuous cornerwhich may be used in the practice of the invention to limit movement ofthe intermediate sheet 26. With reference to FIG. 2, the continuouscorners are formed by portions 58 (see FIG. 2) of the legs 34 and 36 ofthe spacer 30 biased toward one another at the corner over the receivingsurface 40 of the spacer 30. By selectively removing material from thebiased portions 58 of the legs of the spacer, a space is providedbetween the biased portions to accommodate the intermediate sheet. Toprevent damage to the intermediate sheet when such sheet is made ofglass by contacting the bent portions 58, the space between the bentportions can be increased in a manner discussed below. As the bentportions 58 of the legs 34 and 36 are urged toward one another, portions60 of the shaped layer 38 are moved against the intermediate glass sheetand are shown by numeral 60 in FIG. 2.

As can be appreciated, the spacer of The EP Application may be used withmaterial that is sufficiently rigid to hold the sheet as well asmaterials that are not sufficiently rigid. The further advantage of thecontinuous corner is that it provides a continuous non-permeable cornerto moisture and/or gas penetration.

In the instance where the layer 38 is to carry the desiccant to keep thespace between the sheets i.e. compartments dry, the material should be amoisture pervious material. Although the invention is not limitedthereto, materials having a permeability greater than 2 gm mm/M² day asdetermined by the above reference to ASTM F 372-73 are recommended inthe practice of the invention.

As can now be appreciated, the invention is not limited to the number ofcorners of a unit that may have bent portions 58 to limit movement ofthe intermediate sheet 26. For a rectangular unit, two opposite cornershaving bent portions 58 are sufficient to limit movement of theintermediate sheet toward the outer sheets; however, four corners havingbent portions 58 are recommended.

In the practice of the invention a unit similar to the unit 10 shown inFIGS. 1 and 2 was made having rectangular shaped coated, clear glasssheets 22, 24 and uncoated, clear glass sheet 26. Each of the outerglass sheets 22 and 24 had a length of about 427/8 inches (108.9 cm) anda width of about 193/4 inches (50.17 cm). The intermediate sheet had alength of about 421/2 inches (107.95 cm) and a width of about 193/8inches (49.2 cm).

The glass sheets 22 and 24 each had on a major surface a coating of thetype made by PPG Industries sold under its registered trademark Sungate®100 coated glass. The coated surface of each of the sheets 22 and 24faced the intermediate sheet 26.

A spacer having four continuous corners was made as follows. Withreference to FIG. 4, a flat tin coated steel strip 70 has a length ofabout 126 inches (320 cm), a width of about 1.30 inches (3.302 cm) andthickness of about 0.010 inch (0.25 mm) with a tapered and swedged end72 having a hole 74. Opposite end 76 had a hole 78 and receives the end72 when the spacer is positioned around the intermediate sheet. Thetaped end 72 had a length of about 11/2 inch (3.81 cm). Space atlocations about 1.5 inches (3.8 cm), about 211/8 inches (53.65 cm),about 637/8 inches (162.24 cm), and about 831/2 inches (212.09 cm) fromthe end 70, material was removed from opposite edge portion of thesubstrate 70 to provide a set of pair of notches 80, 82, 84 and 86respectively. The notched areas form the bent portions 58 (see FIG. 2),and the notches provide for the bent portions to be a sufficientdistance so as to receive the intermediate sheet. Crease lines 88 wereprovided at the notches as shown in FIG. 4 for ease of bending the bentportions.

Each of the notches of the set of pair of notches 82, 84 and 86 had alength of about 0.536 inch (1.36 cm) at the edge 90 of the substrate, adepth of about 0.170 inch (0.43 cm) as measured from the edge 90 of thesubstrate toward the center of the substrate. The notches 80 weresimilar in size as the notches 82, 84 and 86 but the left side of thenotch as shown in FIG. 4 were further cut to accommodate the end 72. Thedistance between the points of pairs of notches depends on the width ofthe base i.e. the desired spacing between the outer sheets. The unitmade had the point of the crease lines spaced about 0.282 inch (0.71 cm)from the edge of the substrate to provide the base with a width of about21/32 inch (1.67 cm).

After the substrate 62 had the notches, crease lines and holes, thesubstrate is shaped to provide the spacer 30 with the U-shaped crosssection. With reference to FIG. 2, the ends of the upright legs 34 and36 are radiused inwardly to provide stability to the spacer e.g. toreduce flexing of the spacer 20 prior to bending it around the glasssheet 26. After the substrate is shaped, the shaped layer 38 wereprovided by extruding H. B. Fuller HL-5102-X-125 butyl hot melt matrixhaving a desiccant therein is flowed onto the base of the spacer inusing a nozzle arrangement to be discussed below incorporating featuresof the invention. As can be appreciated, the invention is not limited tothe equipment for providing the shaped layer 38. Each of the raisedportions of the shaped layer 28 had a height of 0.125 inch (0.32 cm) anda width of 0.255 inch (0.64 cm) to provide a groove having a depth of0.093 inch (0.23 cm) and a width of 0.125 inch (0.32 cm). It ispreferred to have the material of the layer 38 under the sheet toeliminate any contact between the sheet and the base of the spacer toprevent damage to the edge of the sheet.

In the practice of the invention the flat substrate was cut, notched,shaped, and the adhesive applied using the nozzle of the instantinvention on, equipment sold by Glass Equipment Development Inc. ofTwinsburg, Ohio, Model No. HME 55 PHE-L.

Although not limiting to the invention, after the extrusion of theshaped layer 38, the layers 32 are extruded onto the outer walls of theouter legs 24 and 26 of the spacer 20. The sealant adhesive of the layer32 used was sold by H. B. Fuller as H. B. Fuller 1191 hot melt butyl.The layer 32 had a thickness of about 0.020 inches (0.05 cm) and aheight of about 0.300 inch (0.76 cm).

As can be appreciated, the shaped layer 38 may be extruded onto the baseof the spacer before, after, or during the extrusion of the layers 32onto the side of the spacer.

The intermediate sheet 26 was positioned in the groove 48 of the shapedlayer 38 between the pair of notches 82 and 84. The spacer between thepair of notches 84 and 86 was bent to position the groove 48 of thelayer 38 between the notches 84 and 86 about the edge of the sheet; thespacer between the pair of notches 86 and the end 76 was bent toposition the sheet in the groove 48 of the layer 38 therebetween. Thetapered end 72 was bent to a 90° angle, and the spacer was bent toposition the groove 48 of the spacer layer 38 between the pair ofnotches 80 and 82 about the intermediate sheet. The tapered end 72 wastelescoped into the end 76 of the spacer. As the spacer was positionedabout the glass sheet 26, the bent portions 58 at the corners moved theadhesive of the shaped layer 38 toward the corner of the glass sheet 26as previously discussed.

The outer glass sheets 22 and 24 were thereafter positioned over thesealant adhesive 32 and biased toward one another to flow the adhesive32 and secure the outer glass to the spacer. Thereafter the adhesive 44was flowed into the channel formed by the peripheral edges of the sheetsand the base of the spacer.

As can be appreciated the holes 74 and 78 in the substrate for the unitmade were aligned with each and with the edge of the intermediate sheet.Therefore the hole was sealed with polyol polyisobutylene and sealedover with the adhesive layer 44. In the practice of the invention, it isrecommended that the hole or holes (shown in FIG. 4 as dotted lines 92)be offset from the intermediate sheet 26 and a close end rivet used tosecure the ends of the spacer together. In this case the polyolpolyisobutylene is not required to seal the compartment.

The discussion will now be directed to a nozzle incorporating featuresof the invention used to provide the shaped layer 38. With reference toFIGS. 5-7 there is shown nozzle arrangement 100 having a conditioningchamber 102 and a nozzle 104 secured thereto in any convenient mannere.g. by screws. The conditioning chamber 102 is connected by hose orconduit 106 to a supply of the adhesive material (not shown). In theinstance where the material is a hot melt adhesive, the conditioningchamber 102 is provided with heating elements to heat the adhesive toits flow temperature; in the instance where the adhesive is a twocomponent adhesive, the adhesive is mixed in the conditioning chamber102.

With specific reference to FIGS. 6 and 7, the nozzle 104 has a base 108supporting a raised platform 110 having a pair of opposite flat sides112 clearly shown in FIG. 6. The platform 110 has a forming surfaceincluding a forming tip 114 that forms the shaped layer 38 in a mannerto be discussed. The forming tip 114 has a generally arrow shaped end116 narrower than opposite end 118. The end 116 is lower in height thanthe end 118 with the end 118 sloping toward the platform 110 as shown bynumeral 120 in FIG. 7. In practice the U-shaped spacer 30 advances fromleft to right as shown in FIG. 7. As the lead end of the spacer 30engages the tip 114 the sloped end 120 biases the leading end of thespacer downward as viewed in FIG. 7 against conveyor 122 in thoseinstances where the lead end of the spacer is raised. As the spaceradvances past the nozzle 104 the adhesive is extruded through holes 124and 126 onto the base of the spacer as the forming tip 124 shapes theadhesive to provide the shaped layer 38 on the base of the spacer.

In the practice of the invention for making the unit discussed above,the base 108 had an outside diameter of about 21/2 inches (6.35 cm) anda thickness of about 1/4 inch (0.635 cm). The platform 110 had a heightof about 3/8 inch (0.95 cm). The platform was circular with a diameterof about 0.52 inch (1.37 cm) except for the flat sides 112 that arespaced from each other about 0.485 inches (1.23 cm) and each have alength of about 0.23 inch (0.53 cm). The tip 114 at the narrow end 116has a width of about 0.028 inch (0.020 cm) and expands toward the centerline of the tip to a width of about 0.062 inch (0.157 cm). The slopesurface 120 starts at the edge of the platform 110 and terminates about0.125 inch (0.37 cm) therefrom. With reference to FIG. 7, the tip 114 atthe sloped end 118 has a height of about 0.080 inch (0.20 cm) and at thenarrow end 116 of about 0.065 inch (0.165 cm). The holes 124 in theplatform each had a diameter of about 0.120 inch (0.3 cm) and the hole126 in the tip had a diameter of about 0.093 inch (0.236 cm).

In practice, H. B. Fuller adhesive HL-5102-X-125 having a desiccanttherein is heated to about 250° F. (482° C.). As the U-shaped spacer 30moves past the nozzle 104, the platform 110 is positioned between theouter legs 34 and 36 of the spacer with the highest portion of the tip114 e.g. end 118 of the tip spaced about 1/32 inch (0.08 cm) from thebase 42 of the spacer 36. As the spacer 30 moves past the nozzle thesloped end 120 urges the leading edge of the spacer downward, if lifted,toward the conveyor as adhesive is extruded from the holes 124 and 126to provide the shaped layer 38.

The narrow portion of the tip and the step of the tip prevent tailing ofthe adhesive when the flowing e.g. pumping or extrusion of the materialis stopped. It is expected that providing a step for the platform 110similar to that of the tip will further ensure elimination of tailing.

With reference to FIGS. 8 and 9, there is shown nozzle 130 havingplatform 132. The nozzle 130 is similar to the nozzle 104 except theplatform 132 is provided with a lower portion 134 and a raised portion136 and the platform and nozzle where the change in elevation occurs isradiused surface 140 as shown in FIG. 8. It is expected that theradiused surfaces 140 and change in elevation will eliminate tailing.

The term "tailing" as used herein is the noted effect that occurs whenthe flowing e.g. pumping or extrusion of the material is stopped but dueto the adhesive adhering to the nozzle, strings of adhesive are pulled.

In the instance where an insulating unit e.g. the unit 20 shown in FIGS.1 and 2 has an insulating gas between adjacent glass sheets 22, 26 and26, 24, the insulating gas may be flowed into the compartment betweenthe glass sheets in any convenient manner. For example and withreference to FIGS. 10 and 11 there is shown injector arrangement 150that may be used to move an insulating gas into a compartment whileremoving air in the compartment through a single spacer hole. Theinjector arrangement 150 includes a spring biased bifurated member 152having outer legs 154 and 156 connected to a base 158. The spring member152 is made of spring metal such that the legs 154 and 156 are springbiased toward one another to engage the glazing unit in a mannerdiscussed below. The member 152 used in the practice of the inventionwas a binder clip.

An inner tube 160 has an enlarged end 162 mounted in a housing 164 andpasses through the housing. The tube 160 extends beyond the housing andouter tube 166 and is shown in FIG. 11 as end 168. The end 168 of thetube 160 is sized for insertion through the base 42 of the spacer 30(see FIG. 2). The housing 164 has a hole 170 that provides access to thehollow interior of the housing. The outer tube 166 has end connected tothe housing 164 and has external threads thereon. The housingarrangement is secured to the base 158 of the member 152 by passing theouter tube through a hole (not shown) in the base 158. A nut 172threaded on the outer tube 166 engages O rings 174 on each side of thebase 158 about the tube 166 to capture the base between the housing 164,the O rings 174 and the nuts 172 as shown in FIG. 11.

In practice the end 162 of the inner tube 160 is connected to an Argonsupply (not shown), and the injector arrangement clamped to the unit byspreading the legs 154 and 156 apart by urging members 180 and 182toward one another and inserting the end 168 of the inner tube 160 in ahole (not shown) in the spacer e.g. aligned holes in the substrate 70.The members 180 and 182 are released to clamp the nozzle arrangement 152on the edge of a unit as shown in FIG. 12. It is recommended that theclamp engage the glass at the edge assembly of the unit e.g. edgeassembly 28 of the unit 20 shown in FIG. 2, to prevent damage to theglass. As Argon moves into the unit through the inner tube 168, air inthe compartment between the sheets is displaced and moves out of thecompartment through the annulus between the outer tube 166 and the innertube 160 through the housing 164 and out of the hole 170. After thecompartment is filled with Argon the nozzle is removed and the holesealed in any convenient manner e.g. with a sealant or a closed endrivet.

When the unit has one chamber e.g. as taught in The EP Application, onenozzle centrally located as shown in FIG. 12 is preferred. When the unithas two or more compartments e.g. unit 20 shown in FIG. 2, one nozzlemay be used for each compartment or a nozzle arrangement having twonozzles may be used e.g. nozzle arrangement 194 shown in FIG. 13.

As can now be appreciated the invention is not limited to making atriple glazed unit. For example as shown in FIG. 14 there is a unit 200having four glass sheets 22, 24 and 202. When more than three sheets areused, a blank or spacer 204 may be used between glass sheets 202 shownin FIG. 14. Further, the intermediate sheet may have a hole drilledtherein to interconnect the compartments of the triple glazed unit.

Further, the invention contemplates a multi sheet glazed unit of thetype shown in FIGS. 15 and 16. The unit 250 shown in FIGS. 15 and 16 hasouter sheets 252 and 254 separated by the edge assembly 28 and anintermediate sheet 256 (clearly shown in FIG. 16). The outer sheets 252and 254 have different peripheral configurations and peripheraldimensions, and the intermediate sheet 256 has peripheral dimensionsless than the peripheral dimension of the outer sheet 252.

What is claimed is:
 1. A glazing unit having at least three sheets,comprising:a pair of sheets defined as a first sheet and a second sheet;a spacer between the first and second sheets to provide a space betweenthe first and second sheets, the spacer having a first upright leg and asecond upright leg, each upright leg joined to a base and spaced fromone another such that the base and upright legs have a U-shaped crosssection, each of the upright legs has an outer major surface and aninner major surface opposite to the outer major surface with the innermajor surfaces facing one another, the base having a receiving surfacewith the receiving surface of the base facing the space between thefirst and second sheets and the inner major surfaces of the uprightlegs, wherein selected portions of the upright legs are bent toward andspaced from one another; a moisture and gas impervious sealant securingthe first sheet to the outer surface of the first upright leg andsecuring the second sheet to the outer surface of the second uprightleg; a sheet defined as an intermediate sheet in the space between theselected portions of the upright legs bent toward and spaced from oneanother, and a pliable, flowable material on the receiving surface ofthe base between the inner surface of the first upright leg and theintermediate sheet, defined as a first bead, and on the receivingsurface of the base between the inner surface of the second upright legand the intermediate sheet defined as a second bead, the first andsecond beads and selected portions of the upright legs maintaining theintermediate sheet in position between and spaced from the first andsecond sheets.
 2. The glazing unit of claim 1 wherein the sheets areglass sheets and the spacer and the sheets have four corners to providethe glazing unit with four corners and wherein:the selected portions ofthe upright legs are provided by the spacer at at least two cornershaving the first and second upright legs bent toward one another overthe receiving surface of the base with the bent portions of the uprightlegs biasing the first and second beads toward the intermediate sheet;the first and second beads are a moisture and gas pervious materialhaving a desiccant therein, and further comprising: an insulating gasbetween the first and second glass sheets and the intermediate glasssheet.
 3. The glazing unit of claim 2 wherein the first and secondsheets have peripheral edges and the spacer is recessed between the thefirst and second sheets and spaced from the peripheral edges of thefirst and second sheets to provide a peripheral channel around the unitand further including a sealant in the channel.
 4. The glazing unit ofclaim 2 wherein the intermediate sheet has peripheral edge portions andfurther including a layer of the pliable, flowable material between thefirst and second beads and between the receiving surface of the base andthe peripheral edge portions of the intermediate sheet.
 5. The glazingunit of claim 2 wherein the pliable, flowable material has a Shore AHardness of less than 45 after 10 seconds of flowing.
 6. The glazingunit of claim 2 wherein at least one of the sheets has an environmentalcoating on at least one major surface.
 7. The glazing unit of claim 2wherein the first and second sheets have similar peripheralconfiguration and peripheral dimensions.
 8. The glazing unit of claim 2wherein the first and second sheets have different peripheralconfigurations and peripheral dimensions.
 9. The glazing unit of claim 2wherein the intermediate sheet has peripheral dimensions equal to orless than one of the first and second sheets.
 10. The glazing unit ofclaim 1 further including a second intermediate glass sheet between thefirst and second outer sheets to provide the unit with four glasssheets.